677 research outputs found
AGT/Z
We relate Liouville/Toda CFT correlators on Riemann surfaces with boundaries
and cross-cap states to supersymmetric observables in four-dimensional N=2
gauge theories. Our construction naturally involves four-dimensional theories
with fields defined on different Z quotients of the sphere (hemisphere and
projective space) but nevertheless interacting with each other. The
six-dimensional origin is a Z quotient of the setup giving rise to the
usual AGT correspondence. To test the correspondence, we work out the RP
partition function of four-dimensional N=2 theories by combining a 3d lens
space and a 4d hemisphere partition functions. The same technique reproduces
known RP partition functions in a form that lets us easily check
two-dimensional Seiberg-like dualities on this nonorientable space. As a bonus
we work out boundary and cross-cap wavefunctions in Toda CFT.Comment: 56 pages. v2: Clarify discrete theta angle. v3: Published in JHEP;
extra references. v4: Minor sign fix; extra reference
Modified permittivity observed in bulk Gallium Arsenide and Gallium Phosphide samples at 50 K using the Whispering Gallery mode method
Whispering Gallery modes in bulk cylindrical Gallium Arsenide and Gallium
Phosphide samples have been examined both in darkness and under white light at
50 K. In both samples we observed change in permittivity under light and dark
conditions. This results from a change in the polarization state of the
semiconductor, which is consistent with a free electron-hole
creation/recombination process. The permittivity of the semiconductor is
modified by free photocarriers in the surface layers of the sample which is the
region sampled by Whispering Gallery modes.Comment: 8 pages, 3 figure
Towards achieving strong coupling in 3D-cavity with solid state spin resonance
We investigate the microwave magnetic field confinement in several microwave
3D-cavities, using 3D finite-element analysis to determine the best design and
achieve strong coupling between microwave resonant cavity photons and solid
state spins. Specifically, we design cavities for achieving strong coupling of
electromagnetic modes with an ensemble of nitrogen vacancy (NV) defects in
diamond. We report here a novel and practical cavity design with a magnetic
filling factor of up to 4 times (2 times higher collective coupling) than
previously achieved using 1D superconducting cavities with small mode volume.
In addition, we show that by using a double-split resonator cavity, it is
possible to achieve up to 200 times better cooperative factor than the
currently demonstrated with NV in diamond. These designs open up further
opportunities for studying strong and ultra-strong coupling effects on spins in
solids using alternative systems with a wider range of design parameters.Comment: 20 pages, 9 figure
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